1773. ROUND THE WORLD. 21 Q 



at all times of the tide ; which here, as well as at the 

 other islands, rises about four or five feet, and is high 

 water on the full and change days about seven o'clock. 

 The island of Tongatabu is shaped something like an 

 isosceles triangle, the longest sides whereof are seven 

 leagues each, and the shortest four. It lies nearly in 

 the direction of E. S. E. and W. N. W. is nearly all of 

 an equal height, rather low, not exceeding sixty or 

 eighty feet above the level of the sea. This island, 

 and also that of Eaoowe, is guarded from the sea by 

 a reef of coral rocks extending out from the shore 

 one hundred fathoms more or less. On this reef the 

 force of the sea is spent before it reaches the land or 

 shore. Indeed, this is, in some measure, the situation 

 of all the Tropical Isles in this sea that I have seen ; 

 and thus nature has effectually secured them from 

 the encroachments of the sea, though many of them 

 are meer points when compared to this vast ocean. 

 Van Diemen's Road, where we anchored, is under 

 the north-west part of the island, between the most 

 northern and western points. There lies a reef of 

 rocks without it, bearing N. W. by W. over which the 

 sea breaks continually. The bank does not extend 

 more than three cables lengths from the shore; with- 

 out that, is an unfathomable depth. The loss of an 

 anchor, and the damage our cables sustained, are suf- 

 ficient proofs that the bottom is none of the best. 



On the east side of the north point of the island 

 (as Mr. Gilbert, whom I sent to survey the parts, 

 informed me,) is a very snug harbour, of one mile or 

 more in extent, wherein is seven, eight, and ten 

 fathoms water, with a clean sandy bottom. The 

 channel, by which he went in and out, lies close to 

 the point, and has only three fathoms water ; but he 

 believes that farther to the N. E. is a channel with a 

 much greater depth, which he had not time to ex- 

 amine. Indeed, it would have taken up far more 

 time than I could spare to have surveyed these parts 

 minutely ; as there lie a number of small islets and 



